The field the of the invention relates generally to data processing, and more specifically to methods and systems for managing and performing searches on configurable products.
Java 2 Platform, Enterprise Edition (J2EE) is a set of technologies and specifications developed by Sun Microsystems and supported by many computer and software vendors. J2EE is an environment for developing and deploying enterprise applications. The J2EE platform includes a set of services, application programming interfaces and protocols that provide the functionality for developing multi-tiered, web-based applications.
J2EE applications are made up of components. A J2EE component is a self-contained, functional software unit that is assembled into a J2EE application with its related classes and files and that communicates with other components. The J2EE specification defines the following J2EE components: (1) application clients and applets that run on the client; (2) Java Servlet and JavaServer Pages (JSP) technology components that run on the server; and (3) Enterprise JavaBeans (EJB) components that run on the server.
J2EE components are assembled into a J2EE application verified to be well-formed (i.e., syntactically correct) and in compliance with the J2EE specification, and deployed to production, where they are run and managed by the J2EE server. Deployment is the process whereby software is installed into an operational environment. Deployment descriptors (DDs) are XML files provided with each application that describes how the application should be deployed. DDs are used by the J2EE runtime execution environment to provide and enforce the quality of service attributes described in the DD.
An enterprise bean is a component that implements a business task or business entity and resides in an EJB container, either as an entity bean, a session bean, or a message-driven bean. A container is a standardize runtime environment that provides specific component services. An entity bean represents persistent data maintained in a database. An entity bean can manage its own persistence or delegate this function to its container. An entity bean is identified by a primary key. A primary key in an EJB is the subset of its attributes that are guaranteed to be unique. Persistence mechanisms in EJB containers are closely tied to databases. Entity beans map cleanly to tables. Each column maps to an attribute and each row maps to an entity. If the container hosting the entity bean crashes, the entity bean, its primary key and any remote references survive the crash. A message-driven bean is an asynchronous message consumer. A message-driven bean has no state for a specific client, but its instance variables may contain state across the handling of client messages, including an open database connection and an object reference to a EJB object. A client accesses a message-driven bean by sending messages to the destination for which the bean is a message listener. A session bean is created by the client and usually exists only for the duration of a single client-server session. A session bean performs operations such as calculations or accessing a database for the client. Although a session bean may be transactional, it is not recoverable should a system crash occur. Session bean objects can be either stateless or can maintain conversational state across methods and transactions. If a session bean manages state, then the EJB container manages this state if the object must be removed from memory. However, the session bean object itself must manage its own persistent data.
Extensible Markup Language (XML) enables definition of the tags (markups) needed to identify the content, data, and text in XML documents. It differs from HTML, in that HTML has fixed tags that deal mainly with style or presentation. XML tags use angle brackets as delimiters and identify the data rather than specifying how to display it. The XML approach is to wrap each data item in start/end tags; i.e., <start tag name> data <end tag name>. XML documents are well-formed with every tag having an identical closing tag, and with all tags completely nested. Attributes are bundled in with the start tag and take the form attribute-name=“attribute-value”. XML documents undergo a transformation into a language with style tags under the control of a stylesheet before it can be presented by a browser or other presentation mechanism. Typically, XML is transformed into HTML for presentation. J2EE deployment descriptors are expressed in XML with schemas defining allowed elements.
XML Schema Definition (XSD) specifies a formal description for the elements in an XML document. An XML schema represents the interrelationship between the attributes and elements of an XML object. The XSD description can be used to verify that each item of content in a document adheres to the description of the element in which the content is to be placed. XSD is written in XML and therefore does not require intermediate processing by a parser. Elements are defined within a set of tags as in XML or HTML. XSD is also self-documenting. XML schema provide two basic kinds of datatypes: primitive and derived. A primitive datatype is not defined in terms of other types. Examples of primitive datatypes are string, Boolean, float, double, decimal, binary, ID, IDREF. A derived datatype is defined in terms of existing datatypes. Examples of derived datatypes built into the XML schema are language, integer, date, time.
An XML schema includes a preamble followed by declarations. The preamble is a group of at least three attributes within the <schema> element. The different possible attributes are name, ref, type, use, value, id and form. The declarations allow the description of datatypes, element types, element attributes and content models. XML schema provide two types of datatype definitions. Simple definitions are used to create derived datatypes; complex definitions are used to describe content models. A simple type definition is a set of constraints on the value space and lexical space of a datatype. A complex type definition is a set of attribute declarations and a content type that pertain to the attributes and children of the element that is being specified. An <attribute> declaration associates an attribute name with a specific simple datatype. An <element> declaration provides a description that can be used for validation, provides value constraints, establishes constraining relationships between related elements and attributes. An element may contain annotation elements, datatype declarations (simple of complex), and related child elements. An element has a number of different possible attributes including name, ref, type, minOccurs, maxOccurs, default, fixed and id. The attributes minOccurs and maxOccurs describe the cardinality of child elements. The attribute minOccurs represents the minimum number of occurrences allowed; maxOccurs represents the maximum number of occurrences allowed with the default value the same as the value of minOccurs if no value is specified.